It’s the new release from Dingoo Technologies. I got one to satisfy my curiosity, but sadly it disappoints on many levels.

Dingoo A330

I made up a new version of Dingux that takes advantage of the added memory and faster clock speed. To do that, I needed to get a serial port in there for testing. Unlike the A320, the 330 seems to just have half a port; TX but no RX. So you can get debug data out, but you can’t interact with it. Sucky.

Probing for the RX Line

The TX data is found on a single unmarked testpoint that lies beneath the LCD screen, in the upper middle part of the motherboard. In hopes of finding the RX line, I did some probing to the copper traces around the CPU in the area of the TX line, but neither of my two most-promising candidates proved to be RX data. It is probably not connected at all. More sucky.

A330 Motherboard

I stuck the serial port on the left-hand side of the Dingoo, above the reset button. It was the only clear spot on the motherboard, but it turns out the left speaker wants to sit there, and the serial port keeps failing on me – I have to take it apart and fiddle with it to get it working again. The A330 disappoints on many levels.

10 Comments

Hello,
how its going with serial port? I just got a new A330 today and looking for mods. I found serial line mod for A320 where it was pretty straighfwd because of Rx, Tx marks on silk screen. I googled more but I found only your site about this topic. It’s some months after so anything new? Nobody found Rx yet? I can’t belive they left the pad disconnected under chip. Is there some program that would show received bytes on the screen? Then I could test some pins by injecting data through a resistor…

I spent an afternoon testing possible suspects for the RX line and came up with nothing. “unofficial” word from the company confirmed that there is no RX line; they really did leave it unconnected.

If you wanted to keep up the search, you could use Minicom, connect it to ttyS0 and if it detects anything that would show up on the screen. I don’t know if someone has already compiled it for Dingux but the source is readily available.

Personally I have been out of the dingoo scene for a few months now, so I don’t have any new information.

Thanks for quick reply. And how did you tested the Rx without minicom? Do you have a contact to someone from company that could provide some info about HW? How they debug it – console via USB? Maybe there would be a ossibility. Some ARM MCU (I work with smaller ST ARM9) has variable IO peripheral mapping. This mean that e.g. UART0 can be mapped to say 2 or thee different pin pairs and you select it by config register the alternate function of the pin. But it would require, that those pins will be unused but routed out. This gives not much chances. Maybe lucky the Rx is located in some most outer balls of BGA and could be tapped by fine wire.

I have also question to wireless module. Could it be used for bidirectional communication or it’s just a receiver from gamepad?

The CPU on the A330 is the same as the one on the A320, a JZ4732 MIPS. At least, that’s what it is on the A330 that I have. The ‘other dingoo’ company might have made another a330 but I don’t have any information about that.

Ah, there’s a lot of confusing info about the CPU. In the original firmware is the string “JZ4740-IPU”. The architecture is differently named as Xburst or JzRISC and should be ?compatible? with MIPS32r2…
Somewhere else I found: “Jz4732 = Jz4740 + secret usb boot code rom”

JZ4740 datasheet says this:
UART0_TxD – P12, C15 (TDO)
UART0_RxD – M12, B14 (TDI)
(shared with JTAG)
UART1_RxD – N12
UART1_TxD – R11
So only UART1_TxD is in outer line. But I think they should have routed out the JTAG which is shared with UART0. So somewhere in bootloader it could be reconfigured. Tomorrow I’ll open in and look closer. Unfortunatelly I don’t have x-ray eyes, yet…